ASUS already announced its second-generation add-on ThunderboltEX II series cards and both the single-port ThunderboltEX II and the dual-port ThunderboltEX II DUAL should be shipping pretty soon.
Based on Intel's DSL5320 and DSL5520 chipsets, the new Thunderbolt add-on cards bring support for Thunderbolt 2.0 standard offering up to 20Gbps of bandwidth via single cable.
Both cards use PCI-Express 2.0 x4/x16 slot and need a special header used for timing, low-level system interface or end-to-end DisplayPort via Thunderbolt.
The list of supported motherboards can be found on ASUS' product page via link below.
Source:
ASUS.com,
via Techpowerup.com.